Method and apparatus for transmitting or receiving paging in wireless communication system

ABSTRACT

The present invention relates to a method and apparatus for effectively transmitting or receiving paging in a wireless communication system supporting a plurality of services. A method for transmitting paging by a base station in a wireless communication system supporting a plurality of services according to an embodiment of the present disclosure comprises the steps of: transmitting information on a paging slice corresponding to a service in which paging is transmitted to a terminal; and transmitting the paging to the terminal through the paging slice.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 15/754,109, filed on Feb. 21, 2018, which has issued as U.S. Pat.No. 10,659,993 on May 19, 2020, and is a U.S. National Stage applicationunder 35 U.S.C. § 371 of an International application numberPCT/KR2016/008862, filed on Aug. 11, 2016, which was based on andclaimed priority under 35 U.S.C § 119(e) of a U.S. Provisionalapplication Ser. No. 62/208,198, filed on Aug. 21, 2015, in the U.S.Patent and Trademark Office, the disclosure of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present invention generally relates to a method and apparatus fortransmitting and receiving paging in a wireless communication system,and more particularly, to a method and apparatus for transmitting andreceiving paging in a wireless communication system that supports aplurality of services.

BACKGROUND ART

In order to meet wireless data traffic demand, which has increased sincethe commercialization of a 4th Generation (4G) communication system,efforts to develop an improved 5G communication system or a pre-5Gcommunication system have been made. For this reason, the 5Gcommunication system or the pre-5G communication system is referred toas a beyond 4G network communication system or a post LTE system.

In order to achieve a high data transmission rate, the implementation ofthe 5G communication system in a super-high frequency (mmWave) band(e.g., 60 GHz band) is being considered. In the 5G communication system,technologies such as beamforming, massive MIMO, Full Dimensional MIMO(FD-MIMO), an array antenna, analog beam-forming, and a large scaleantenna have been discussed to mitigate propagation path loss in thesuper-high frequency band and to increase a propagation transmissiondistance.

Further, technologies such as an evolved small cell, an advanced smallcell, a cloud radio access network (cloud RAN), an ultra-dense network,device to device communication (D2D), a wireless backhaul, a movingnetwork, cooperative communication, coordinated multi-points (CoMP), andinterference cancellation have been developed to improve the systemnetwork in the 5G communication system.

In addition, in the 5G system, there have been developed advanced codingmodulation (ACM) schemes such as hybrid FSK and QAM modulation (FQAM)and sliding window superposition coding (SWSC), and advanced accesstechnologies such as filter bank multi carrier (FBMC), non orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA).

Meanwhile, the Internet has been evolved to an Internet of Things (IoT)network in which distributed components such as objects exchange andprocess information from a human-oriented connection network in whichhumans generate and consume information. An Internet of Everything (IoE)technology may be an example in which a big data processing technologythrough a connection with a cloud server or the like is combined withthe IoT technology.

In order to implement IoT, technical factors such as a sensingtechnique, wired/wireless communication, network infrastructure, serviceinterface technology, and security technology are required, andtechnologies such as a sensor network, Machine to Machine (M2M)communication, Machine Type Communication (MTC), and the like for aconnection between objects are recently being researched.

In an IoT environment, an intelligent Internet Technology (IT) servicethat collects and analyzes data generated from connected objects, andcreates a new value for peoples' lives may be provided. IoT may beapplied to fields, such as smart home, smart building, smart city, smartcar, connected car, smart grid, health care, smart home appliance, orhigh-tech medical services, through the convergence of the conventionalIT and various industries.

Research on communication technologies for a next generationcommunication system such as the 5G communication system has beenconducted, and one of the examples of the communication technologies isa technology for supporting a plurality of Quality of Services (QoS) ina wireless communication system that supports a plurality of services.As a New Radio (NR) study item that is discussed by 3rd GenerationPartnership Project (3GPP) as an example of a communication system thatsupports the plurality of QoSs, a communication system is beingdesigned, in which a physical layer frame (PHY frame) structure forsatisfying QoS which is different for each service (or slice) and asub-carrier spacing are optimized for each service. In the communicationsystem, an independent paging signal is transmitted for each service. Inthis instance, a UE that supports a plurality of services needs toindependently receive a paging signal transmitted for each service. Whenthe UE is in an idle state, the amount of power consumed by the UE mayincrease.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

According to aspects of the present invention, a method and apparatusfor efficiently transmitting and receiving paging in a wirelesscommunication system that supports a plurality of services, and acommunication method and apparatus using the same are provided.

According to aspects of the present invention, a method and apparatusfor transmitting and receiving paging, which reduce the amount of powerconsumed in a wireless communication system that supports a plurality ofservices are provided.

According to aspects of the present invention, a method and apparatusfor transmitting and receiving cross-slice paging in a wirelesscommunication system that supports a plurality of services are provided.

According to aspects of the present invention, a method and apparatusfor an efficient RACH procedure in a wireless communication system thatsupports a plurality of services are provided.

According to aspects of the present invention, a method and apparatusfor operating a paging period for each service in a wirelesscommunication system that supports a plurality of services are provided.

According to aspects of the present invention, a method and apparatusfor setting a PF/PO for paging in a wireless communication system thatsupports a plurality of services are provided.

Technical Solution

According to embodiments of the present invention, a method fortransmitting paging by a base station in a wireless communication systemsupporting a plurality of services includes: transmitting, to a userequipment (UE), information on a paging slice corresponding to a servicein which paging is transmitted; and transmitting the paging to the UEthrough the paging slice.

According to embodiments of the present invention, a base station in awireless communication system supporting a plurality of servicesincludes: a communication interface for communicating with other networkentity; and a controller for controlling transmitting, to a UE,information on a paging slice corresponding to a service in which pagingis transmitted, and transmitting the paging to the UE through the pagingslice.

According to embodiments of the present invention, a method forreceiving paging by a user equipment (UE) in a wireless communicationsystem supporting a plurality of services includes: receiving, from abase station, information on a paging slice corresponding to a servicein which paging is transmitted; and receiving the paging through thepaging slice.

According to embodiments of the present invention, a UE in a wirelesscommunication system supporting a plurality of services include: acommunication interface for communicating with other network entity; anda controller for controlling receiving, from a base station, informationon a paging slice corresponding to a service in which paging istransmitted, and receiving the paging through the paging slice.

According to embodiments of the present invention, a rule fordetermining the paging slice may include at least one of (1) selecting aslice minimizing delay, (2) selecting a high-capacity slice, (3)selecting a low-power slice, (4) selecting a slice with low pagingloading in a Tracking Area Unit (TAU) area, and (5) selecting a slicethat secures a larger amount of resources (to which a larger amount ofresources is allocated) in a corresponding TAU area, according to a keyperformance priority.

According to embodiments of the present invention, adeferring/supplementary (deferring) operation which may be performedwhen a paging reception error occurs may include at least one of: (1) anoperation of transitioning to a sleep state without UE's pagingreception, (2) an operation of extending a time window (PF/PO: PagingFrame/Paging Occasion) for receiving paging, and (3) a paging sliceextending operation, that is, an operation of receiving paging through acandidate slice, excluding a paging resource designated as a pagingslice. The options for the deterring/supplementary (deferring)operation, the size of a time window for receiving paging, andinformation on a candidate slice may be determined by an MME. In thesetting operation, the MME may determine a paging deferring option andrelated parameters in consideration of mobility of a UE among basestations as idle mobility. A base station may receive settinginformation from the MME, and may signal the same to a UE whenconfiguring or releasing RRC for the UE.

According to embodiments of the present invention, a message fortransferring the paging may include at least one of a slice identifier,RACH related information, and information on an activated slice,together with a UE identifier, and the RACH related information includesRACH option information for performing RACH using one of an RACHresource of the paging slice, an RACH resource for each slice, a commonRACH resource, and an earliest RACH resource.

According to embodiments of the present invention, by adding, as a newfield, information for distinguishing whether the corresponding RACH isMO/MT, and slice information of downlink data that arrives at aconnection request corresponding to Message 3 in the earliest RACHprocedure, RRC (re)configuration (Message 4) is immediately performedwith respect to the corresponding service even when cross-slice RACH isperformed.

According to embodiments of the present invention, the operation oftransitioning to an RRC_connected state by a UE after performing theRACH procedure may include at least one of: an operation of activatingall of the slices of the UE; an operation of activating some of theslices of the UE, and particularly, activating a slice corresponding toa service of traffic indicated by paging that arrives at the UE; and anoperation of activating some of the slices of the UE, and particularly,activating a paging slice, irrespective of a service of trafficindicated by paging that arrives at the UE.

According to embodiments of the present invention, a new PF and a new POare set for receiving paging for each service (slice), and a pagingperiod Tc is separately operated for each service (in consideration ofQoS delay), and Tc is operated using a multiple (e.g., an integermultiple), whereby Tx/Rx duration may be minimized.

According to embodiments of the present invention, UEs that receivepaging of the same service are grouped, and the UEs operate as the samepaging indicator group.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an operation of setting cross-slicepaging in a wireless communication system that supports a plurality ofservices according to embodiments of the present invention;

FIG. 2 is a diagram illustrating an operation of receiving cross-slicepaging in a wireless communication system that supports a plurality ofservices according to embodiments of the present invention;

FIG. 3 is a diagram illustrating an example of adeferring/supplementation (deferring) operation when an error occurs incross-slice paging reception by a UE according to embodiments of thepresent invention;

FIG. 4 is a diagram illustrating an example of an operation oftransitioning an RRC idle state into an RRC_connected state byperforming RACH when paging arrives at a UE, and an example of RACHresources according to embodiments of the present invention;

FIG. 5 is a diagram illustrating an effect of an earliest RACH(cross-slice RACH) in a wireless communication system that supports aplurality of services according to embodiments of the present invention;

FIG. 6 is a diagram illustrating an earliest RACH procedure in awireless communication system that supports a plurality of servicesaccording to embodiments of the present invention;

FIG. 7 is a diagram illustrating an example of a signaling procedure foractivating a deactivated slice when DL traffic arrives at thedeactivated slice according to embodiments of the present invention;

FIG. 8 is a diagram illustrating an example of a method of operating apaging period for each service in a wireless communication system thatsupports a plurality of services according to embodiments of the presentinvention;

FIG. 9 is a diagram illustrating an example of a method of controlling aDRX offset for each service for setting a PF/PO according to embodimentsof the present invention;

FIGS. 10A and 10B are diagrams illustrating an example of setting aPF/PO group according to embodiments of the present invention;

FIG. 11 is a diagram illustrating a method of setting a PF/PO groupwhich uses a paging indicator according to embodiments of the presentinvention; and

FIG. 12 is a diagram illustrating the configuration of an apparatusaccording to embodiments of the present invention.

MODE FOR CARRYING OUT THE INVENTION

In the following description of embodiments of the present invention, adetailed description of known functions or configurations incorporatedherein will be omitted when it is determined that the detaileddescription thereof may unnecessarily obscure the subject matter of thepresent invention.

Hereinafter, various embodiments of the present invention will bedescribed with reference to the accompanying drawings. The embodimentsand the terms used therein are not intended to limit the technologydisclosed herein to specific forms, and should be understood to includevarious modifications, equivalents, and/or alternatives to thecorresponding embodiments. In describing the drawings, similar referencenumerals may be used to designate similar constituent elements. Asingular expression may include a plural expression unless they aredefinitely different in a context. As used herein, singular forms mayinclude plural forms as well unless the context clearly indicatesotherwise. The expression “a first”, “a second”, “the first”, or “thesecond” may modify corresponding elements regardless of the order orimportance, and is used only to distinguish one element from anotherelement, but does not limit the corresponding elements. When an element(e.g., first element) is referred to as being “(functionally orcommunicatively) connected,” or “directly coupled” to another element(second element), the element may be connected directly to the anotherelement or connected to the another element through yet another element(e.g., third element)

The expression “configured to” as used in various embodiments of thepresent invention may be interchangeably used with, for example,“suitable for”, “having the capacity to”, “designed to”, “adapted to”,“made to”, or “capable of” in terms of hardware or software, accordingto circumstances. Alternatively, in some situations, the expression“device configured to” may mean that the device, together with otherdevices or components, “is able to”. For example, the phrase “processoradapted (or configured) to perform A, B, and C” may mean a dedicatedprocessor (e.g., embedded processor) only for performing thecorresponding operations or a generic-purpose processor (e.g., CentralProcessing Unit (CPU) or Application Processor (AP)) that can performthe corresponding operations by executing one or more software programsstored in a memory device.

Further, in the specification, a User Equipment (UE) may have variousnames such as a Mobile Station (MS), a terminal, and a device, and aBase Station (BS) may have various names such as an eNB and an AccessPoint (AP).

Embodiments of the present invention to be described below may beapplied to operations of a base station and a UE for achieving energyefficiency key performance indicators (KPI), which is being discussed in3GPP radio access network (RAN) 5G Study Item (SI). A technology that isbeing discussed in 3GPP RAN 5G SI of 3GPP is related to an energyefficiency operation which can dramatically increase power efficiency ofa UE and base station network. Also, research on a technology ofreducing the amount of time expended for a measurement operation and anactive operation of a corresponding cell is being conducted in order toovercome the probability of additional power consumption according to abeamforming transmission scheme which is required for a millimeter wave(mmW) operation in a high-frequency band. Also, technologies provided inembodiments of the present invention are related to a method ofefficiently configuring a paging operation so as to improve powerefficiency of a UE and/or base station when a plurality of services aresupported in a New RAT (NR)-based wireless communication system.

Hereinafter, terms used in the present specification will be brieflydefined. “Paging” indicates a paging signal transmitted or received in awireless communication system, a paging message transmitted through apaging operation, or a paging operation thereof “Slice” indicates aservice provided in the wireless communication system. In the presentspecification, a slice and a service may be used interchangeably forease of description, and they are understood as having the same orsimilar meanings. An example of the service, a New RAT-based servicewhich is being discussed in 3GPP RAN5G SI of 3GPP may include anenhanced mobile service (eMMB), massive Machine Type Communication(mMTC), Ultra Reliable and Low Latency Communications (URLLC), or thelike. The eMMB is an improved mobile broadband service, and may be aservice that requires a massive capacity data transmission, such asUltra High Definition (UHD) service, a hologram image service, a virtualreality service, or the like. The mMTC may be a communication serviceamong massive devices (i.e., a plurality of UEs), such as a massiveInternet of Things (IoT) service, or the like. The URLLC may be aservice that requires ultra-high reliability and low latencycommunication, such as factory automation, a remote operation, anautonomous driving vehicle, or the like. A service to which theembodiments of the present invention may be applied may not be limitedto eMMB, mMTC, and URLLC, and may include various services that requiredifferent QoSs. The various services may be provided, for example, inthe same system which is based on 5G. “Paging slice” indicates a slice(i.e., service) that transmits paging. “Cross-slice” indicates one slice(or a plurality of slices) selected for transmitting paging from among aplurality of slices which are capable of providing a service to a UE.“Cross-slice paging” indicates paging transmitted through a cross-slice.

An example of different QoS required for each service, New RAT-basedeMMB, mMTC, and URLLC, is listed in Table 1 provided below.

TABLE 1 eMBB mMTC URLLC Data Rate Very high Not much Not much (e.g. peakconsidered considered rate 10 Gbps) Latency Low Not much Very Lowconsidered (e.g. 1 ms end-to-end) Mobility 0 km/h to Not much Not much500 km/h considered considered Reliability Not much Not much Very Highconsidered considered (e.g. Packet loss rate: as low as le-04) Power Notmuch Very Low Not much Consumption considered considered Connection High(e.g. 200- Very High High Density 2500 UEs/km²) (e.g. 1 M (e.g. 10 kconnections/km²) sensor/10 km²)

Also, as shown in Table 1, QoS characteristics of each service, whichmay be supported by the same system, are different for each service andthus, the transmission characteristics of each service may be designedto be different for each service. For example, transmissioncharacteristics, such as a frequency band (High/Low frequency) for eachservice, a frequency width (Wide/Narrow bandwidth), a transmissionperiod (PHY Numerology (Subframe length, carrier spacing)), or the likemay be designed to be different according to the characteristics of QoSof each service. A UE capable of supporting a plurality of services(slices) in the same system that supports a plurality of services isreferred to as a UE having multi-slice capability (hereinafter, referredto as a multi-slice capable UE or a UE). When the multi-slice capable UEindependently receives paging which is independently transmitted foreach service, the amount of power consumed by the multi-slice capable UEwhich is in an idle state may dramatically increase.

Therefore, embodiments of the present invention propose a method ofenabling an idle-state UE to perform operation even though the UEreceives paging for a single slice, instead of receiving paging for eachslice, in order to reduce the burden of receiving paging for eachservice. As the single slice, a low-power slice or a low-latency slicemay be used.

The embodiments of the present invention design a paging receptionoperation, which is an idle-state operation performed by a multi-slicecapable UE in a wireless communication system that supports a pluralityof services, as cross-slice based paging reception instead of receptionfor each slice, whereby UE power efficiency is improved and datatransmission delay is kept to a minimum. Conditions related to thepaging operation of the present invention are, for example, as follows.

Condition 1) when a cross-slice paging operation is performed bycrossing paging for multiple slices over one or a plurality of slices,the procedure and time for transmission and reception need to kept to aminimum and the transmission of paging information for all UEs in a cellneeds to be performed without delay.

Condition 2) the amount of power consumption calculated even taking intoconsideration an additional operation of a UE during a paging operationin order to minimize the procedure and time for transmission andreception of the improved cross-slice paging needs to have higher powerefficiency than a conventional method

The operation for the cross-slice paging which has been proposed in theembodiments of the present invention may be performed through thefollowing four steps.

Step 1: set a paging slice for each UE

Step 2: receive system information (SI) for receiving cross-slicepaging, and receive a paging message designed based on cross-slicepaging

Step 3: operate as slice-based RACH or early RACH in an RACH operationfor transitioning from an RRC_idle state to an RRC_connected state aftera UE receives paging (here, the description of the slice-based RACH andearly RACH will be described later.)

Step 4: activate the entirety or a part of UE's slice resources at thetransition to RRC_connected state

Through the step 1 to step 4, the paging reception operation by theidle-state UE in a New RAT communication system that supports aplurality of services is performed as a cross-slice based pagingreception operation, instead of a paging reception operation for eachslice, whereby UE power efficiency may be expected to be improved.

According to embodiments of the present invention, improvement of UEpower efficiency may reduce the number of radio resources of a targetthat receives paging (or frequency and on duration time in a DRXoperation of a UE) by performing a cross-slice paging receptionoperation, instead of performing a multi-slice paging receptionoperation that independently receives paging for multiple slices. Also,in the case of single slice paging reception, a paging operation isperformed through a low-power slice instead of a high-power slice,whereby an idle-state UE may reduce the amount of power consumed forperforming a paging operation with respect to one slice. Also, a delayoccurring when the state of a UE is changed from an RRC_idle state intoan RRC_connected state may be reduced by utilizing RACH resourcesallocated for each slice through cross-slice, whereby UE powerefficiency may be improved and delay performance may be also improved.

According to embodiments of the present invention, an example of theconfiguration of step 1 to step 4 for cross-slice paging will bedescribed as follows.

Step 1: based on a UE's capability feedback reflecting a slicesupportable for each UE and energy efficiency information of acorresponding slice, a network entity (e.g., Mobility Management Entity(MME)) that manages the UE's mobility may determine a paging slice. Asanother example, the MME may determine a paging slice based on the UE'ssubscription information, instead of the UE's feedback information. Thesubscription information may be provided from, for example, a HomeSubscriber Server (HSS). The base station may receive information on apaging slice determined by the MME, and may indicate the correspondingpaging slice to a UE. The base station may provide information forsetting the paging slice to the UE through control signaling.

Step 2: for paging reception, system information (SI) includes common SIbroadcasted such that all UEs can receive the same, and slice-dedicatedSI which corresponds to a slice required for cross-slice paging. Thecommon SI may include at least one of information on a common slice andindication information on the slice-dedicated SI. The slice-dedicated SImay be set for each slice (service). A UE receives system information(SI) for receiving paging, and receives a paging message designed basedon cross-slice paging. New fields may be included in the paging messagetogether with a UE ID, in order for a paging reception operation in apaging slice. The new fields may include at least one of fieldsassociated with, for example, a slice indicator, an RACH, and anactivation slice option. The detailed description of the new fields willbe described later. Also, in embodiments of the present invention,examples of deferring/supplementary (deferring) operations that may beperformed when an error occurs in the paging reception by a UE are (1)to (3) as provided below.

(1) an operation of immediately transitioning to a sleep state withoutthe UE's paging reception

(2) an operation of extending a time window (PF/PO: Paging Frame/PagingOccasion) for receiving paging

(3) a paging slice extending operation, that is, an operation ofreceiving paging through a candidate slice which is different from apaging resource designated as a paging slice

Options for the deferring operation that is performed when a pagingreception error occurs, and the size of a time window for pagingreception, information on a candidate slice, or the like may be set bythe MME. In the setting operation, the MME may determine and set apaging deferring option and related parameters in consideration ofmobility of a UE among base stations as idle mobility. A base stationmay receive setting information from the MME, and may provide thesetting information to a UE when RRC is configured or released for theUE.

Step 3: when it is determined that traffic arrives at a corresponding UEwhen paging is received, examples of available options for an RACHoperation of the UE are (1) to (4) as provided below.

(1) common slice RACH: an operation of transitioning an RRC_Idle stateto an RRC_connected state using common RACH resources which areindependent from a slice

(2) slice-dedicated RACH: an operation of transitioning an RRC_Idlestate to an RRC_connected state using RACH resources for each slicebased on a service of paged traffic, wherein, in the case of theslice-dedicated RACH, a UE needs to be aware of RACH settings of allslices, in advance, and thus, may need to receive SI for each of all theservices, which may be burdensome.

(3) Cross-Slice RACH (performing RACH using a paging slice): anoperation of transitioning an RRC_Idle state to an RRC_connected stateusing an RACH resource of a paging slice, irrespective of a service oftraffic indicated by paging that arrives at a UE, wherein the pagingslice is determined in advance, and thus, the UE may know thecorresponding paging slice before receiving paging. Therefore, the UEneeds to receive only SI for each service of the corresponding pagingslice, whereby the UE may reduce the burden of receiving SI.

(4) Cross-Slice RACH (performing RACH using an early slice): anoperation of transitioning an RRC_idle state to an RRC_connected stateusing an RACH resource of a paging slice, irrespective of a service oftraffic indicated by paging that arrives at a UE, wherein the UE needsto know RACH settings of all slices since the UE utilizes the earliestRACH resource, which is the closest to an arbitrary point. Therefore,the UE has the burden of receiving SI for each service, but the UEutilizes the earliest RACH resource which is the closest to an arbitrarypoint, whereby the delay of an operation of transitioning an RRC_idlestate to an RRC_connected state may be reduced and the user delay QoSmay be improved. Also, when the cross-slice RACH operation is performed,in an RRC configuration transitioned from an RRC_idle state to anRRC_connected state, a UE needs to report service information ofcorresponding traffic to a base station. Accordingly, by addinginformation for distinguishing whether the corresponding RACH isMobility Originated (MO)/Mobility Terminated (MT) and slice (service)information to a new field(s) of a connection request corresponding tomessage 3 in the existing RACH procedure, RRC (re)configuration(corresponding to message 4 in the existing RACH procedure) isimmediately performed with respect to the corresponding service evenwhen cross-slice RACH is performed, whereby data transmission delay maybe avoided when a connected-state operation is performed.

Step 4: an operation of transitioning to an RRC_connected state by a UE,after an RACH procedure. In the operation in step 4, an option foractivating slice resources of a UE may include at least one of: anoperation of activating all of the slices of the UE; an operation ofactivating some of the slices of the UE, and particularly, activating aslice corresponding to a service of traffic indicated by paging thatarrives at the UE; and an operation of activating some of the slices ofthe UE, and particularly, activating a paging slice, irrespective of aservice of traffic indicated by paging that arrives at the UE.

The above described embodiments of the present invention haveillustrated an operation of receiving system information for receivingpaging according to a cross-slice paging setting and an operation optionfor power reduction of a multi-slice capable UE, an operation ofperforming slice RACH to an RRC_connected state, and an operation ofactivating a slice. According to embodiments of the present invention,services (slices) supported by a multi-slice capable UE may include aslice capable of supporting an improved QoS, such as a slice having highlink capacity, a slice with low delay, or the like. A low energyconsumption slice supports relatively low QoS from among servicessupported by a multi-slice capable UE, but consumes a small amount ofpower, whereby the low energy consumption slice may be advantageous fromthe perspective of energy efficiency.

Hereinafter, embodiments of the present invention will describeoperations of step 1 to step 4 for cross-slice paging in detail.

<Step 1: Cross-Slice Paging Setting Operation>

FIG. 1 is a diagram illustrating an operation of setting cross-slicepaging in a wireless communication system that supports a plurality ofservices according to various embodiments of the present invention. Theoperation of FIG. 1 includes an operation of setting a paging sliceindication for a UE based on UE capability information, in order to setcross-slice paging.

Referring to FIG. 1, in operation 101, a UE 10 transmits UE slicingcapability information to a base station 30. The information is based onUE capability information that takes into consideration energyefficiency for each slice. A paging slice may be set for each UE, andcapability feedback (i.e., UE slicing capability information) reflectinga slice supportable for each UE and energy efficiency information of acorresponding slice may be transmitted from the UE 101 to the basestation 30. An MME 50 that receives the capability feedback from thebase station 30 determines a paging slice for the UE 10, and transfersinformation on the determined paging slice (hereinafter, paging sliceinformation) to the base station 30 in operations 103 and 105. Inoperation 107, the base station 30 transmits the paging sliceinformation to the UE 10 through control signaling for RRCconfiguration. In operation 109, the base station 30 transmits datatraffic to the UE 10. The paging slice information may be transmitted tothe UE 10 through control signaling for RRC reconfiguration or releaseas described in operation 111.

Subsequently, when the UE 10 is switched into an idle state in operation113, paging transmitted to the UE 10 is transmitted in a paging sliceindicated by the paging slice information in operations 115 and 117. Inoperation 119, the UE 10 receives paging in a paging occasion (PO)calculated for the reception of paging.

In the present embodiment, as a method of indicating a multi-slicepaging option, 1) and 2) provided below may be used.

1) a slice-independent paging method, that is, a method of independentlytransmitting each slice paging according to a conventional operation

2) a cross-slice paging method, that is, a method of transmitting pagingthrough one slice selected from among a plurality of slices capable ofproviding a service to a UE

A method of indicating the paging slice information in the presentembodiment is the cross-slice paging method, that is, a method ofsetting, for a UE, one slice selected from among a plurality of slicescapable of providing a service to the UE.

Table 2 provided below is an example of priorities of slices accordingto a rule for selecting a paging slice. The rule for selecting a pagingslice for each UE in the example of Table 2 may include at least one of(1) selecting a slice minimizing delay, (2) selecting a high-capacityslice, (3) selecting a low-power slice, (4) selecting a slice with lowpaging loading in a tracking area unit (TAU) area, and (5) selecting aslice that secures a larger amount of resources (a slice to which alarger amount of resources is allocated) in a corresponding TAU area,according to a key performance priority.

TABLE 2 Option Paging slice Example of paging index selection criterionslice priority 1 select slice minimizing delay {circle around (1)}URLLC > eMBB > mMTC {circle around (2)} URLLC > mMTC > eMBB 2 selecthigh-capacity slice {circle around (1)} eMBB > mMTC > URLLC {circlearound (2)} eMBB > URLLC > mMTC 3 Select low-power slice {circle around(1)} mMTC > URLLC > eMBB {circle around (2)} mMTC > eMBB > URLLC 4Select slice with low {circle around (1)} URLLC > eMBB > mMTC pagingloading in {circle around (2)} URLLC > mMTC > eMBB corresponding {circlearound (3)} eMBB > mMTC > URLLC TAU area {circle around (4)} eMBB >URLLC > mMTC {circle around (5)} mMTC > URLLO > eMBB {circle around (6)}mMTC > eMBB > URLLC 5 select slice that secures larger {circle around(1)} URLLC > eMBB > mMTC amount of resources (slice to {circle around(2)} URLLC > mMTC > eMBB which larger amount of {circle around (3)}eMBB > mMTC > URLLC resources is allocated) in {circle around (4)}eMBB > URLLC > mMTC corresponding TAU area {circle around (5)} mMTC >URLLC > eMBB {circle around (6)} mMTC > eMBB > URLLC

A method of transmitting paging slice information to the UE 10, afterthe MME 50 determines a paging slice, and informs the base station 30 ofthe paging slice, may be based on option 1 and option 2 provided below.

Option 1) explicit indication of a paging slice: a control signalingmethod that explicitly indicates a paging slice for each UE

Option 2) implicit paging slice rule transmission: a method of providinga UE with a rule for determining a paging slice for each UE

According to the method based on the option 1, paging slice informationmay be transmitted through control signaling which is for controlling apredetermined UE, such as RRC (re)configuration and/or RRC release forconfiguration between a base station and a UE in the RRC_connectedstate.

In the method based on the option 2, the paging slice selection rule maybe applied to a cell, a TAU, or an MME through system information suchas an MIB, SIBx, or the like.

As another method of transmitting the paging slice information, a methodof primarily transmitting information indicating whether paging existsfor each slice through a paging indicator, and indicating paging sliceinformation which is to be transmitted when paging is actually performedmay be used.

<Step 2: Cross-Slice Paging Reception Operation>

FIG. 2 is a diagram illustrating an operation of receiving cross-slicepaging in a wireless communication system that supports a plurality ofservices according to various embodiments of the present invention.

Referring to FIG. 2, in operation 201, a UE receives common SIbroadcasted such that all UEs can receive the same. The common SI mayinclude at least one of information on a common slice and indicationinformation on slice-dedicated SI. For example, the common SI mayinclude the minimum information, thereby reducing the burden oftransmitting a common control signal. The common SI additionallytransmits indication information for slice-dedicated SI (slice dedicatedSI info), for example, [Broadcast period, Radio Resource], in additionto information on a downlink included in an existing MIB, for example[Bandwidth, SFN, Scheduling Info], thereby indicating a receptionresource of the slice-dedicated SI to be transmitted.

In operation 203, a UE that receives the common SI receives theslice-dedicated SI based on the indication information for theslice-dedicated SI. The slice-dedicated SI may transmit a parametersetting different for each service, and may transmit slice-dedicatedpaging information, for example, [Parameter, Slice Dedicated RACHresource configuration information required to calculate a Paging periodand a Paging Frame/Paging occasion].

In this instance, SI that a UE needs to receive may be changed accordingto a cross-slice paging option. For example, all UEs need to receive thecommon SI. In the case of the slice-dedicated SI, a UE receives SIcorresponding to a slice required for cross-slice paging. In the case ofPO time window extension reception, according to an operation ofreceiving paging through a candidate slice, a UE may also receive SIrelated to a candidate slice.

In operation 205, a UE that receives the slice-dedicated SI receives apaging message in a slice corresponding to the cross-slice paging.Information included in fields of the payload of the paging message mayinclude at least one of, for example, an existing UE ID, a sliceindicator, an RACH, and information on activation of a slice, as shownin Table 3.

TABLE 3 UE ID Slice Indicator RACH options Slice Activation options 1.Common RACH 1. All Slice Activation 2. Slice Dedicated RACH 2. PagingSlice Partially Activation 3. Earliest RACH 3. Data Arrival SlicePartially Activation

Table 4 provided below provides, for example, 8 operation statesaccording to option values in the fields of the payload of the pagingmessage. The operation states are possible examples of RACH and aconnected state transition operation.

TABLE 4 Slice Indicator RACH options Slice (De)activation options 1 XCommon RACH All Slice Activation 2 X Common RACH Paging Slice activationonly (Slice cross scheduling) 3 X Earliest RACH All Slice Activation 4 XEarliest RACH Paging Slice activation only (Slice cross scheduling) 5 OSlice Dedicated Data arrival slice RACH Activation only 6 O SliceDedicated Paging Slice activation only RACH (Slice cross scheduling) 7 OEarliest RACH Data arrival slice Activation only 8 O Earliest RACHPaging Slice activation only (Slice cross scheduling)

In operation 205, at least one of the above describeddeferring/supplementary (deferring) operations is performed when apaging reception error occurs.

FIG. 3 is a diagram illustrating an example of a deferring/supplementary(deferring) operation when an error occurs in cross-slice pagingreception by a UE according to an embodiment of the present invention.

In operations 301 and 303, the MME 50 determines a paging slice for theUE 10, and transfers information on the paging slice to the base station30. In operation 305, the base station 30 transmits the paging sliceinformation to the UE 10 through control signaling for RRCreconfiguration or release. Subsequently, when the UE 10 is switchedinto an idle state in operation 307, and paging transmitted in operation309 fails to allocate a paging slice in operation 311, paging is nottransmitted in the determined paging slice in operation 313. Examples ofoptions of a possible deferring/supplementary (deferring) operation mayinclude at least one of 1) to 3) of FIG. 3. When paging is transmittedthrough a candidate slice, the UE may receive paging transmitted througha candidate slice in operation 315.

<Step 3: Transition from RRC_Idle State to RRC_Connected State (RACH)>

Referring again to FIG. 2, in operation 207, the UE performs transitionfrom an RRC_idle state to an RRC_connected state through RACH whenpaging arrives at the corresponding UE after the UE receives paging asillustrated in operations 401 to 405 of FIG. 4. According to the presentembodiment, in the three-step operation for transition from the RRC_idlestate to the RRC_connected state after the reception of paging, when itis determined that traffic has arrived at the corresponding UE, thereare options for RACH operation (common slice RACH, slice dedicated RACH,cross slice RACH (performing RACH using a paging slice or performingRACH using an early slice)), which have been described, and thus,detailed description thereof will be omitted.

In the case of cross slice RACH (performing RACH using an early slice),the earliest RACH resource is utilized and delay of the transition fromthe RRC_idle state to the RRC_connected state is decreased, wherebydelay QoS improvement is expected.

FIG. 5 is a diagram illustrating the effect of an earliest RACH(cross-slice RACH) in a wireless communication system that supports aplurality of services according to an embodiment of the presentinvention. Referring to FIG. 5, a UE performs promotion to anRRC_connected state using an RACH resource allocated earlier, such asthe diagram 501, irrespectively of a slice.

FIG. 6 is a diagram illustrating an earliest RACH procedure in awireless communication system that supports a plurality of servicesaccording to an embodiment of the present invention.

Referring to FIG. 6, a UE transmits a PRACH preamble to a base stationin operation 601 of the earliest RACH procedure. The base stationallocates, to the UE, a resource for transmission of Message 3 inresponse to the PRACH preamble in operation 603. The UE requestsconnection based on Message 3 using the allocated resource in operation605. The base station performs RRC connection setup in response to theconnection request in operation 607.

When cross-slice RACH operation is performed according to the earliestRACH procedure of FIG. 6, in the RRC configuration transitioned from theRRC_idle state to the RRC_connected state, the UE needs to inform thebase station of service information of corresponding traffic. To thisend, the present embodiment proposes a method of adding, as new fields,information for distinguishing whether the corresponding RACH is MO/MT,and slice information of downlink data that arrives at a connectionrequest corresponding to Message 3 in the existing RACH procedure, andimmediately performing RRC (re)configuration with respect to thecorresponding service even when cross-slice RACH is performed, wherebydata transmission delay may be avoided when a connected-state operationis performed.

<Step 4: Activation/Deactivation for Each Service in RRC_ConnectedState>

Referring again to FIG. 2, in operation 207, the UE transitions toRRC_connected state, and activates a slice resource of the UE. Examplesof options for activating a slice resource have been described above. Inthis instance, activation or deactivation may be performed for eachslice.

Table 5 shows an example of options for a tagging operation for otherslice arrival information after activating only a paging slice when theUE operates in a connected state in the embodiments of the presentinvention.

TABLE 5 Option Slice Activation Cross-slice scheduling 1 All SliceActivation Not needed 2 Paging Slice Needed activation only (if Pagingslice ≠ Data slice) 3 Data arrival slice Not needed activation only (butactivation need if DL traffic arrives in other slices)

In the present embodiment, when the UE operates in a connected state, across-slice scheduling method according to slice activation is asfollows.

The UE receives scheduling information through an activated slice. Thatis, the UE successively receives PDCCHs through the activated slice orperforms a C-DRX operation.

The UE may not perform reception through other slices.

This method is based on a common/dedicated PDCCH design issue.

Also, the UE performs activation when downlink (DL) traffic arrives at adeactivated slice, and the options thereof are, for example, option 1)to option 3) provided below.

Option 1) RRC Reconfiguration (˜100 s ms)

Option 2) New MAC CE (˜10 s ms)

Option 3) PDCCH DCI new Field (˜1 s ms)

FIG. 7 is a diagram illustrating an example of a signaling procedure foractivating a deactivated slice when DL traffic arrives at thedeactivated slice according to embodiments of the present invention.FIG. 7 illustrates a procedure in which the UE of FIG. 7 activates adeactivated slice when DL traffic arrives at the deactivated slice,after the UE activates a partial slice when the UE operates in aconnected state.

Referring to FIG. 7, the UE receives paging in operation 701, andperforms an RACH procedure in operation 703. Subsequently, in operation705, the UE receives data traffic corresponding to slice 1 (in thisinstance, it is assumed that slice 2 is in a deactivated state). When DLtraffic arrives at the slice 2 in operation 707, the UE activates theslice 2 using at least one of the options 1 to 3 in operation 709.Subsequently, in operation 711, the UE receives DL traffic in theactivated slice 2.

Hereinafter, an embodiment of the present invention for setting a new PFand a new PO for receiving paging for each service (slice) in a wirelesscommunication system of the present invention that supports a pluralityof services will be described. In a normal 3GPP-based communicationsystem, the PF is a frame allocated to a UE for receiving paging, andthe PO is a subframe interval allocated to the UE for receiving pagingfrom among a plurality of subframes included in the PF. The UE mayreceive paging in a subframe that satisfies the PF and PO. An equationfor calculating the PF and PO may refer to the related 3GPP standard.

The embodiments of the present invention propose a method of setting anew PF and PO for receiving paging for each service (slice).

To this end, the present embodiment proposes two methods of setting apaging period for each service, first.

Method 1: separately operating a paging period Tc for each service (inconsideration of QoS delay). A conventional system operates one cellspecific paging period (in the case of Tc transmission, SIB2:RadioResourceConfigCommonSIB), the present embodiment operates a pagingperiod Tc for each service, that is, operates multiple paging periods(Tc1, Tc2, Tc3, . . . etc). In this instance, the nB related standardused for a Tc and PF/PO equation and a paging period transmitted throughSIB may be changed according to the method 1. Here, “nB” denotes aparameter for controlling the frequency of a PF and a PO within a pagingcycle. The related standard is defined as N=Number of paging frames perpaging cycle=min(T, nB), Ns=number of paging subframes in a radio frameused for paging=max (1, nB/T).

Method 2: operating a paging period Tc for each service using a multiple(e.g., an integer multiple), and minimizing a Tx/Rx duration. It isassumed that a paging period for each service is Tc1, Tc2, and Tc3,wherein a PF/PO may be freely set in consideration of QoS. In thisinstance, the paging period for each service may be operated using amultiple, such as Tc2=X Tc1 and Tc3=Y Tc1, and DTX may be maximized.

FIG. 8 is a diagram illustrating an example of a method of operating apaging period for each service in a wireless communication system thatsupports a plurality of services according to embodiments of the presentinvention. Referring to FIG. 8, a paging period for each service is setto be different as shown in the diagram 801, which is an example ofoperating a paging period using a multiple.

According to the present embodiment, in association with a pagingtransmission operation of a base station, a base station activation(transmission) time may be minimized by synchronizing a PF/PO of pagingfor each service. In association with a UE paging reception operation, aUE reception (activation) time may be minimized by synchronizing a PF/POof paging for each service.

Also, the present embodiment proposes a method of controlling a DRXoffset for setting a PF and a PO for each service.

FIG. 9 is a diagram illustrating an example of a method of controlling aDRX offset for each service for setting a PF/PO in a wirelesscommunication system that supports a plurality of services according toembodiments of the present invention.

Referring to FIG. 9, in operations 901 and 903, a base station (e.g., anNR cell) 31 sets a paging period for each service, and transmits, to theUE 10, DRX configuration information including information on a pagingdeferring/supplementary (deferring) rule and DRX offset synchronizationfor each service. The UE 10 is switched into an idle state in operation905, and UE idle mobility occurs in operation 907. Subsequently, pagingfor each service is aggregated through DRX offset synchronization inoperations 909 and 911, and the UE performs an RACH procedure byreceiving the aggregated paging. In the method of FIG. 9, the MME 50sets a DRX for each service, and the UE and a base station may minimizean activation period in the idle state of the UE. DRX offsetsynchronization is performed in a downlink, and DRX offsetsynchronization for each service in the UE is performed. DRX offsetsynchronization among a plurality of UEs is performed. Also, RACHdeferring transmission exists in an uplink, and RACH aggregation foreach service in the UE is performed.

Also, the embodiments of the present invention propose a method oftransmitting a paging period and a PF/PO setting rule through SIB2. Inthe present embodiment, a paging period for each service is set to bedifferent, and a PF/PO group is set.

For example, the same paging rule is applied for each service. In thisinstance, UEs that use the same service have the same paging period andthus, are selected as the same PF/PO group and power efficiency may beimproved as shown in FIGS. 10A and 10B. Also, the present embodimenttransmits a paging period and a PF/PO setting rule (e.g., nB parameter)through the SIB2. In the case in which the paging period and the PF/POgroup, which are set through SIB2, are set, when the UEs that use thesame service are the same PF/PO group, the power efficiency may beimproved.

Also, the embodiments of the present invention propose a method ofproviding paging period (PF/PO) information through a page indicator,without using SIB2 (i.e., omitting an operation of receiving an SI-basedSIB2 including the page indicator). The base station may group UEs thatreceive paging of the same service, and operates them as the same pagingindicator group in the diagram 1101 of FIG. 11. The base stationtransmits paging to each PF/PO group corresponding to different pagingindicators in operations 1103 and 1105, and does not transmit paging toother PF/PO groups. The UE receives a PF/PO group corresponding to apaging indicator, and remaining UEs operate in a sleep state, whereby UEpower reduction may be expected.

FIG. 12 is a diagram illustrating the configuration of an apparatusaccording to embodiments of the present invention. The apparatus of FIG.12 may be applied to the UE 10, the base station 30, and the MME 50.

The configuration of the apparatus of FIG. 12 includes a controller 1201and a communication interface 1203. The controller 1201 controlssignaling related to operations of the apparatus such that paging istransmitted and received through a paging slice according to the methoddescribed in FIGS. 1 to 11, and controls an operation for setting a newPF and PO for receiving paging for each service. The communicationinterface 1203 is for data communication with another network entity,and may be implemented as at least one communication interface forwired/wireless communication such as a transmitter, a receiver, atransceiver, or the like.

As an example, the base station according to embodiments of the presentinvention may be implemented to include the communication interface 1203for communicating with another network entity, and the controller 1201for controlling transmitting, to a UE, information on a paging slicecorresponding to a service in which paging is transmitted, andtransmitting the paging to the UE through the paging slice. As anexample, a UE according to embodiments of the present invention may beimplemented to include the communication interface 1203 forcommunicating with another network entity, and a controller forcontrolling receiving, from a base station, information on a pagingslice corresponding to a service in which transmits paging istransmitted, and receiving the paging through the paging slice.

1. A method of receiving a frame in a broadcast system, the methodcomprising: receiving a frame from a server over a heterogenous networkbased on a motion picture experts group (MPEG) media transport (MMT)protocol, wherein the frame comprises header information and multimediadata, wherein, the header information includes type information anddelay sensitivity information in case that when the generated framesupports quality of service (QoS), wherein the type informationidentifies whether a bit rate is constant or not, and the delaysensitivity information indicates a delay sensitivity of the multimediadata, and wherein the type information and the delay sensitivityinformation are used for flow control over the heterogeneous network. 2.The method as claimed in claim 1, wherein a flow for receiving the frameis controlled based on the type information and a flag included in theheader information.
 3. The method as claimed in claim 1, wherein theheader information further comprises a flow label indicating a QoSrequested for each flow.
 4. The method as claimed in claim 1, whereinthe header information further comprises information about segmentationor combination of the multimedia data.